# 继承,继承具有传递性
class Animal:
    def eat(self):
        print("吃饭")
        pass

    def dink(self):
        print("喝水")
        pass

    def sleep(self):
        print("睡觉")
        pass


class Dog(Animal):
    pass


class XiaoTianQuan(Dog):
    def fly(self):
        print("我会飞")


cat = Animal()
cat.sleep()
dog = Dog()
dog.sleep()

quan = XiaoTianQuan()
quan.fly()
